System and method for the assertion and identification of rights information in an analog video signal

ABSTRACT

A method for processing an analog video signal that represents a work for which rights information is asserted. The signal includes a rights assertion mark (RAM) in the video portion of the signal within the visible picture such that capture of the picture will include the mark. The signal also includes copy control information (CCI) bits in the vertical blanking interval of the signal for representing copying and redistribution rules. If the RAM is present and the CCI bits are present, then the copying and redistribution rules represented by the CCI bits are applied. If the RAM is present but the CCI bits are not, then the most restrictive copying and redistribution rules that can be represented by the CCI bits are applied.

RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisionalapplication Nos. 60/445,660 filed on Feb. 7, 2003, 60/446,726 filed onFeb. 11, 2003, and 60/460,928 filed on Apr. 7,2003.

BACKGROUND

[0002] A. Field of the Invention

[0003] This invention pertains to a system and method for inserting copycontrol information into an analog signal, including a right assertionmark and a CGSM signal.

[0004] B. Description of the Prior Art

[0005] Copyrighted works normally contain associated rights information.In the case of a book, for example, this information might consist ofthe name of the author(s) and the date from which copyright is claimed.In more complex cases, such as those related to transmission ofaudio-visual works over digital transmission media, it may be desirableto convey rights information that goes beyond such basic information.For example, rights information with respect to audio-visual workscould, include information on whether copies may be made of the works,how many copies may be made, and whether the works may be retransmittedto another party.

[0006] There are various methods of transmitting audio-visual works froma source (the point at which the transmission originates, such as aset-top box, or an optical disc player, such as a DVD player) to a sink(the point at which the work is displayed or recorded for laterdisplay). Such methods include robust digital connections using securetransmission technologies such as DTCP on IEEE-1394 high-speed digitallinks or HDCP on DVI digital links. The most common method fortransferring works from a source to a sink utilizes an analog videoconnection with the transmission being an NTSC or PAL composite videosignal. However, when using current techniques, analog delivery does notprovide robust protection for a work.

[0007] In the context of the protection of audio-visual works, the word“robust” refers to the strength of the copy protection. In analogsignaling, the term is used to mean that rights information istransmitted in a way that makes it unlikely that the information wouldbe completely removed inadvertently. In digital signaling, the termindicates that a secure mechanism is used that involves theauthentication of the sink device by the source device. Authenticationensures that the source device can trust the sink device to follow therules. Such secure mechanisms can include the encryption of the rightsinformation and the work during transmission so that any attempt tomonitor the transmission will fail. In addition, the rights informationcan be accompanied by a digital signature, an unforgeable attachment tothe rights information that will indicate if unauthorized alterationsare made to rights information.

[0008] In general, digital links can be robust because the signaling istwo-way, while analog links are limited in their robustness in that thesink device cannot typically communicate with the source device.

[0009] Unfortunately, in converting a digital work to analog form (forexample, an NTSC video signal), the rights information associated withthe digital form of the work may be lost or translated into a form thatcan be subsequently removed. The conversion of the work to an analogvideo signal is necessary to allow the work to be viewed on aconventional television set or video monitor, the majority of which haveonly analog video inputs. However, the conversion of the digital form ofthe work to analog followed by the re-conversion back to a digital formcan be used as a means of circumventing the content protection of thework in a digital form.

[0010] The problem of the loss of rights information this way is knownas the “analog hole” and there are efforts underway to devise ways to“plug” the hole. While certain technologies have been identified andused in an attempt to prevent the loss of rights information uponconversion of digital audio-visual works to analog, there is noequivalently robust protection for protecting analog transmissions ofsuch works that has been accepted for widespread use.

[0011] One technology that has been used for the transmission of rightsinformation in an analog video signal is called CGMS-A. CGMS-A is astandard that conveys copy control information (CCI) in the non-visiblevertical blanking interval (VBI) of a video signal (FIG. 1). The VBI isthe period during which the display device resets its scan line from thebottom of the picture to the top. In NTSC encoded video signals, theCGMS-A information is carried on either or both of lines 20 and 21 ofthe picture (FIG. 2), which lines are transmitted during the VBI. CGMS-Acarries a 2-bit CCI value which can convey the information “copy never”,“copy one generation”, “copy control not asserted” and, in mostdefinitions of CGMS-A, a fourth state of “copy no more.”

[0012] Redistribution of an audio-visual work occurs when that work ismade available other than through the original distribution meansauthorized by the rights owner. For example, an audio-visual work is“redistributed” if it is recorded from a free-to-air broadcast and therecording is then made available on the Internet. In-home recording offree-to-air broadcasts is popularly understood to be permitted for theprivate use of the person making the recording. It is not permitted totake a recording made in this way and make it available to others. To doso constitutes redistribution. Recently a retransmission control (RC)bit has been defined in some CGMS-A standards such as 805A. The RC flagis designed to signal that the content cannot be retransmitted. The RCbit is a third bit of CCI. Herein, the term CGMS-A will include the RCbit unless specifically stated otherwise.

[0013] Unfortunately the CGMS-A information occurs in a part of thesignal that is not displayed and consequently the loss or removal of theinformation carried in this part of the signal does not affect thequality of the picture (although it may cause the loss of otherinformation carried in this part of the picture such as closed captiontext). CGMS-A is, therefore, not a robust signaling method. Not only canthe CGMS-A bits be removed, but because CGMS-A is not required to bepresent in the video signal and is also trivial to remove, it is notpossible to tell whether a video signal has had CGMS-A removed orwhether it was even there to begin with.

[0014] Historically, watermarks are designs pressed into paper at thetime of manufacture to identify the maker. A paper watermark is almostcompletely invisible until the paper is held up to the light.Watermarking is also the term used for the process of embedding aconcealed mark that conveys or indicates rights ownership in a stillpicture, or video or audio signal such that it is not apparent to theviewer/listener.

[0015] Detection of CGMS-A information is simple, requiring no morecomplexity than is required to interpret an analog video signal fordigitization or display. By comparison, the detection of embeddedwatermarks is often complex, involving advanced signal processingparticularly when the watermark to be detected is embedded in the image.The added complexity of detecting a watermark normally adds cost to thedevice that is required to detect the watermark. Nevertheless, it hasbeen proposed to combine CGMS-A and a watermark in an audio-visual workto provide greater robustness to the analog form of the work.

[0016] U.S. Pat. No. 6,433,946 in the name of Ogino that issued on Aug.13, 2002 and is entitled “Information Signal Output Control Method,Information Signal Duplication Prevention Method, Information SignalDuplication Prevention Device, And Information Signal Recording Medium”proposes using a combined watermark and CGMS-A approach to control playand copying (but not redistribution) of an audio-visual work. The CGMS-Amark is not used in the usual way. Instead, it represents a “don't copy”command only. Not only does the system utilize less information than canbe represented by a CGMS-A code, but the watermark in the firstembodiment of the Ogino system is redundant with the CGMS-A code. Ifboth signals are present, it means that the audio-visual work has notbeen tampered with, i.e., it is not an illegal copy. Copies are notpermitted in accordance with the two codes, but the work is played. Butif only one of the two codes is present, it is an indication that therehas been tampering. In this case, not only is copying disabled, but thework is not even played. Only if both signals are absent is copyingallowed along with play. In this embodiment of the Ogino system, thereis symmetry between the watermark and the CGMS-A signals—the same copyand play controls apply if only one of the signals is present,regardless of which one it is.

[0017] The second Ogino embodiment is the same as the first, with onedifference. If the GGMS-A signal is present but the watermark is not,play is not inhibited. But it is accompanied by a message that the playis improper. Play is allowed so that the user will not think that thereis anything wrong with his television set, but the play is accompaniedby interference. The basic control mechanism is the same as thefirst—neither signal takes precedence over the other, and the presenceof one signal without the other is an indication that something improperhas taken place before the audio-visual work reached the television set.(In a third embodiment of the Ogino system, which is more sophisticatedin that “re-marking” to a “copy no more” state apparently takes placewhen a work with a “copy one generation” code is played, it is assumedthat the CGMS-A signal is already on an audio-visual work, and awatermark is simply added based on the CGMS-A signal.)

[0018] A major shortcoming of the Ogino system is that in treating theCCI code and the watermark symmetrically, the CCI code can be used torepresent no more than the watermark. That is why the state tables inthe Ogino patent drawing simply have “yes” and “no” entries for whetherthe two signals are present or not. Because the watermark onlyrepresents “yes” or “no”, and the CCI code is treated symmetrically, theCCI code is restricted to represent only “yes” or “no” as well. The fullrange of information that is possible with a CGMS-A code is just notused. Instead of extending use of CGMS-A to a third CCI bit, theretransmission control (RC) bit to indicate whether or not the contentcan be retransmitted, Ogino does not even use the full potential ofCGMS-A in its original form.

[0019] In contrast to the limitations of Ogino, it is an object of ourinvention to provide CCI bits (e.g., in the CGMS-A format) in thenon-visible vertical blanking interval of a video signal in such a waythat, if the bits are removed, it will be possible to tell that theyhave been removed so that appropriate decisions about play andredistribution of the underlying audio-visual work may be made, the CCIbits conveying more information than simply “copy” and “don't copy.”This is accomplished by inserting a video subcarrier component into thevisible portion of the video signal.

SUMMARY OF THE INVENTION

[0020] Like Ogino, we provide both a signal in the visible portion andCCI bits in the non-visible portion of an audio-visual work. But therethe similarity ends as the two forms of information are not otherwisecomparable. The basic control mechanism is the code in the VBI,preferably an extended CGMS-A signal. If it is present, then it isobeyed (with respect to both copying and redistribution) whether or notthe video subcarrier component is present. The video subcarriercomponent, which we refer to as RAM, standing for “rights assertionmark”, has an effect only if the CGMS-A bits are not present. Thepresence of RAM simply represents that a CGMS-A signal was present. Thatis all it represents. If it is present but the CCI bits are not, thenthe sink device defaults to the most restrictive CCI state. In the caseof CGMS-A, this means that copying and redistribution are not permitted.(Play is not controlled at all, as it is in Ogino, since CGMS-A bits donot represent any type of play control.)

[0021] The RAM in the audio-visual work is a robust analog signal thatis easily detected and, if present, indicates that a less robust rightsindicator or signal, such as CGMS-A, is either present or was oncepresent but has been tampered with or removed. The CGMS-A signal remainsdominant. The RAM, while more robust, simply tells the sink devicewhether rights are being asserted.

[0022] Although our invention is not limited to use of a particular RAM,one is highly preferred. U.S. Pat. No. 4,807,031 in the name ofBroughton, et al. that issued on Feb. 21, 1989 and is entitled“Interactive Video Method and Apparatus” discloses a method andapparatus for in-band, video broadcasting of commands to interactivedevices. Control data is encoded into the video image using a“subliminal” modulation scheme, a scheme that can be detectedelectronically but is largely imperceptible to the viewer. The encodingis in a selected sequence of video image fields. The resulting modulatedvideo fields are within the displayed area of the video (the area thatis seen by the viewer), and have alternately proportionately raised andlowered luminance on selected horizontal scan lines. (See FIG. 5.) Asdisclosed in the patent, the modulation is monitored by a lightsensitive device positioned adjacent the user's television screen.

[0023] The modulation of the video signal used by Broughton, et al. isreferred to herein as “VEIL modulation”, VEIL being the commercial nameof the system based on the patent. In a sense, VEIL is simpler andeasier to implement than the watermarking technology employed by Oginoin that the VEIL modulation can be sensed by looking for a singlefrequency in the video signal.

[0024] For further robustness, the information conveyed by the CGMS-Asignal can be confirmed by a secondary CCI indication (SCCI). The SCCIis preferably in watermark form. In the preferred embodiment of theinvention, the SCCI is an audio watermark.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Further objects, features and advantages of the invention willbecome apparent upon consideration of the following detailed descriptionin conjunction with the drawing, in which:

[0026]FIG. 1 is the waveform of a NTSC video signal during the verticalblanking interval;

[0027]FIG. 2 is the waveform of line 21 of an NTSC video signal showingdata embedded in the analog signal;

[0028]FIG. 3 is a block diagram of a typical transmission path for anaudio-visual work showing the points where content marking (rightsassertion mark, SCCI watermark or CGMS-A) is added;

[0029]FIG. 4A is a Rights Assertion Mark (RAM) Logic Table, and setsforth the action to be taken when the presence of the RAM, CGMS-A and RChave been determined (the term CGMS-A includes or does not include theRC bits depending on the context);

[0030]FIG. 4B is an alternate Righst Assertion Mark (RAM) Logic Table;

[0031]FIG. 5 is the waveform of two adjacent horizontal lines in an NTSCvideo signal showing how VEIL modulation operates by raising theluminance of one line and by lowering the luminance of the adjacentline; and

[0032]FIG. 6 is a block diagram of a representative method for detectingthe presence of the VEIL modulation using electronic coupling to thevideo signal rather than the optical coupling to the television screendescribed in U.S. Pat. No. 4,807,031, the block diagram showing how thisdetection is used in parallel with an analog video capture system.

DETAILED DESCRIPTION

[0033] The invention is a system that uses a mechanism called the RightsAssertion Mark (RAM) to indicate that rights have been asserted for thework together with the conveyance of those rights elsewhere in the workin the primary CCI indicator. Optionally, a secondary CCI indicator(SCCI) that conforms to the CCI bits confirms that the CCI informationin the primary indicator has not been altered.

[0034] The RAM has a meaning similar to that of a copyright symbol—©—ona publication; it indicates that rights are asserted in the work. TheRAM is embedded in the video portion of the work within the area of thevisible picture in such a way that the capture of the image will alsocapture the RAM.

[0035] To convey the particular rights information asserted in the work,the RAM is accompanied by a CCI indicator, which in one embodiment maybe CGMS-A information including the RC bit. The CCI indicator conveys,for example, how the work may be used. In the situation where the RAM ispresent, but the CCI indicator is not, this indicates either that theCCI indicator was once present and has been removed, or that the CCIindicator was intended to have been applied to the work, but was not. Insuch situations, certain default rules govern use of the work.

[0036] The system has the advantage of being more robust than CGMS-Asignaling by itself and, since it does not require a complex watermarkembedded in the image portion of the work, it is less costly toimplement than current watermarking techniques.

[0037] For further robustness, the value conveyed by the CGMS-A signalcan be confirmed by the secondary CCI indication (SCCI). The SCCI cantake the form of a watermark. In the preferred embodiment, the SCCI isan audio watermark.

[0038] Using the system of the invention allows the sink device todistinguish between CGMS-A signaling on non-commercial content (such asthe output from a home camcorder) in which a RAM will not be present,and CGMS-A signaling on commercial content in which a RAM will bepresent. This is an important distinction to draw because, for example,in copy protection systems for recordable media such as CPRM, commercialcontent must be protected through encryption when it is recorded andnon-commercial content may not be protected through encryption when itis recorded.

[0039] The presence of the RAM coupled with the absence of CGMS-A fromthe video signal indicates that the CGMS-A signal was lost, stripped ornot properly added to the video signal by the source device. In thiscase, the CCI attached to the work cannot be determined from the primarymechanism and, in the absence of the SCCI, any recording device thatobeys the CCI must not copy the work.

[0040] The system protects against removal of the CGMS-A signal bydevices that only process the visible image and also by circumventiondevices that blank the lines that carry CGMS-A information. If the SCCIis present, the system protects against the alteration of the CGMS-Ainformation from “Copy Never” to a more permissive CCI by providing theability to check that the CGMS-A information is conveying the correctrights.

[0041] The default state conveyed by detection of the RAM is “CopyNever” and “No Retransmission”/ “No Redistribution”. The presence of CCIinformation can alter these defaults. For example, the presence of twobits of the CGMS-A CCI and the third RC bit can permit other uses suchas “Copy Once” and “Copy Freely, No Redistribution Allowed”.

[0042] As described earlier, CGMS-A is a system for copy control. In asystem that uses only CGMS-A, the absence of CGMS-A means that use ofthe content is unrestricted. Therefore, removal of CGMS-A removesrestrictions. By contrast, in a system that uses, for example, CGMS-Aaccompanied by a RAM, the presence of the RAM indicates thatrestrictions are imposed regardless of whether CGMS-A is present or hasbeen removed. In such a system, the presence of a RAM can be used toconvey a default set of rules governing the use of the content, and thepresence of CGMS-A can be used to further define permissions, which willtypically be less restrictive than the default set of rules, as to howthe content may be used. This is an important distinction between theRAM system and other systems. Unless the RAM mark is removed, tamperingwith the mechanism that conveys the copy control information can onlymake usage permissions more restrictive.

[0043] The RAM can take many forms, both visible and invisible.Preferably, it is in the visible portion of the work and is easy todetect. The following list of alternatives is illustrative, notexhaustive:

[0044] 1. A concealed mark (which does not need to be a complexwatermark).

[0045] 2. A visible mark such as a sequence of dots in the picturesimilar to the cue marks on film prints that signal the change over fromone reel to the next.

[0046] In the preferred embodiment of the invention, the mark isconcealed both so that the mark does not interfere with viewing thework, and in order to make removal difficult using, for example, a toolsuch as PC video editing software.

[0047] In the preferred embodiment of the invention, VEIL modulation isused to convey the Rights Assertion Mark (RAM). VEIL modulation isdescribed in detail in U.S. Pat. No. 4,807,031, discussed above. FIG. 6shows how the RAM signal can be detected. Since alternate lines havetheir luminance values increased and decreased, a complete cycle ofincrease/decrease requires two line scans. This means that the VEILsignal occurs at half the line frequency, so all that is required todetect it is a circuit that detects a signal occurring at half the linefrequency. By using a high-Q Band Pass filter, as shown in FIG. 6, theVEIL frequency can be isolated. It is then rectified and tested againsta threshold. (The Visible Line Horizontal Sync Detector at the input ofthe RAM Detection circuit is provided so that the filter operates ononly visible lines of a complete frame. Since the VEIL signal is notincluded on lines in the VBI, the filter should not operate on theselines.)

[0048] The RAM is a bit sequence (binary number) or pattern encoded intofields or frames of the work using VEIL modulation such that thedetection system has a very low false positive indication of thepresence of the RAM and an acceptably low false negative indicationwhere it fails to detect the presence of the RAM. The use of awell-known bit sequence or pattern will distinguish the presence of theRAM from other control information that may also be encoded into thevideo using VEIL modulation.

[0049] The VEIL modulation encoded RAM is resilient to casual attack.The RAM can be anywhere in the work. It is not required to be on anyparticular field or frame of the work, or on any particular line withina field or fields, and it can be inserted repeatedly into the work.Removal thus requires a certain level of sophistication in anycircumvention method or device. An improved VEIL modulation scheme isdescribed in application No. ______ filed on even date herewith,entitled “Method for Encoding Data in an Analog Video Signal Such Thatit Survives Resolution Conversion”, which application is herebyincorporated by reference.

[0050] Since the RAM need only communicate by its presence the simplestatement of “rights asserted” indicating that the CCI is conveyed byanother mechanism, there is no need to encode any data into the VEILmodulated RAM.

[0051] Alternatively, VEIL modulation can be used to convey both RAM andCCI information. For example, the RAM might be extended from a singlevalue to one of several values that indicate the rights informationincluding “copy never” and “copy one generation.”

[0052] It is necessary to accommodate conversion between multiple videostandards, for example the North American standard 525 interlaced systemand the ATSC 720 progressive and 1080 interlaced and progressive scansystems. Such conversion is commonly referred to as “up res'ing”indicating that the conversion involves an increase in pictureresolution and “down res-ing” indicating that the conversion involves adecrease in resolution. To achieve survivability of such video standardconversion the RAM is encoded into the work multiple times using aplurality of variants of the VEIL modulation scheme. Each variant hasdifferent parameters such that at least of one of the variants can stillbe detected and decoded after any one of the anticipated conversions invideo standard.

[0053] The optional SCCI (secondary CCI indicator) does not need to bein the visible portion of the work. A preferred embodiment of the SCCIis an industry accepted commercially available audio watermark, theVerance digital watermark used in DVD audio.

[0054] Another method to verify the correctness of the CCI is the use ofa digital signature attached to the CGMS-A information. Such a CGMS-Asignature uses additional data fields in one of the video lines that areused to send data such as CGMS-A and closed captions, for example, line20 or line 21. The CGMS-A signature is computed using a one-way hashfunction, a nonce derived from one or more picture frames, and the CCIvalue of the CGMS-A. It is only necessary to use the CGMS-A signature onCCI values other than “Copy Never” since there is no advantage to begained by altering the CCI information to “Copy Never.”

[0055] The nonce is derived from a predetermined portion of a frame orframes using an integration technique based on the value of luminancefor a known set of the visible pixels in that set of frames. Basing thecalculation of the luminance is the preferred method so that thesignature survives the conversion of the picture to black and white.

[0056] The signature is calculated for insertion before the work istransmitted and before conversion from its digital representation to ananalog representation. δ = H(ϕ + ∫_(i)¹λ(i))

[0057] where δ is the digital signature; H is the one way hash function;φ is the CCI value (two bits for CGMS-A); + is the concatenationoperator; N is the number of pixels being used to generate the nonce;and λ(i) is the luminance value of pixel i.

[0058] When the work is received and converted from its analogrepresentation to a digital representation the digital signature isrecalculated and the value compared with the signature transmitted inthe analog signal. The signature calculated from the re-converted analogsignal will likely not be exactly the same as the original signature dueto noise in the analog video signal. To accommodate for this noise, thecomparison between the received CGMS-A signature and the calculatedCGMS-A signature must take these variations in the re-generatedsignature into consideration and techniques to do this exist.

[0059] The work is created by the content creator, for example, a studiothat produces a movie, and is made ready for distribution. Before thework is distributed the content creator adds rights information to thedigital embodiment of the work in three different steps, as shown inFIG. 3.

[0060] Step 1. The CCI is stored in the rights container that is part ofthe digital format. For example, in the case of a DVD, the DVD standardrequires a player to add CGMS-A to its output analog signal.

[0061] Step 2. The RAM is added to the work in a predefined standardizedmanner, in the preferred embodiment using Veil modulation.

[0062] Step 3. Optionally, the content creator can chose to add theSCCI, for example, by embedding a standard audio watermark in the work.Should the content creator choose not to embed the SCCI watermark, arecorder will not be able to determine the CCI if it detects the RAM inthe absence of CGMS-A.

[0063] The system provides protection against unauthorized analogre-conversion as described above. Before analog re-conversion can takeplace, the digital version of the work has to be converted to an analogsignal by a source device. This is a normal occurrence because many sinkdevices have only analog inputs. The CGMS-A information on the videosignal from the source device can come from one of two places: (1) it isalready present in the signal if the work was delivered by a videotransmission system where the source device is, for example, a set topbox, or (2) the CGMS-A may be added to the analog signal by the sourcedevice if the source device is, for example, an optical disc player.

[0064] If the sink device is capable of digitizing the analog signalusing an analog-to-digital converter, it will check for rightsinformation embedded in the analog video signal in three differentplaces—the RAM, the two CGMS-A CCI bits, and the RC bit.

[0065] The RAM logic table of FIG. 4A summarizes the overall systemoperation. As mentioned above, the invention allows the sink device todistinguish between CGMS-A signaling on non-commercial content (such asthe output from a home camcorder) in which a RAM will not be present,and CGMS-A signaling on commercial content in which a RAM will bepresent. A sink device looks for the CGMS-A information. If it is notpresent (lines 6 and 7 of the table), the sink device looks for the RAM.If it is also not present, the assumption is that the work isnon-commercial and has no rights asserted. Copying is therefore notcontrolled (line 6). The same applies to redistribution of the work.Copying and redistribution are both unrestricted. But if the RAM ispresent, and the CGMS-A information is not, it is an indication thattampering with the information has occurred. The sink device writes new“Copy Never” CGMS-A information in the work, copying is not permitted,and redistribution is similarly not allowed (line 7).

[0066] In the case of line 1 of the table of FIG. 4A, the redistributionentry is “RC bit, else not controlled.” What this means is that if theRC bit is present, its state controls whether redistribution is allowed.If the bit is not present, then no control is asserted overredistribution.

[0067] In the next four lines (lines 2 through 5) of the table, theredistribution entry is “RC bit, else not allowed”. What this means isthat if the RC bit is present, its state controls whether redistributionis allowed. If the bit is not present, then redistribution is notallowed.

[0068] If the CGMS-A information is “Copy freely”, copying is allowed.But the form the copying takes depends on whether the RAM is present. Ifit is not present, copying of any form is allowed (line 1). If the RAMis present, indicating that rights are asserted, then while copying isallowed, it has to be done in a protected way—the copying has to beencrypted or protected in some other way.

[0069] If the CGMS-A information is “Copy Once” (line 3), then obviouslyrights are being asserted. A single encrypted copy is all that isallowed, and that copy is marked “Copy No More.”

[0070] If the CGMS-A bits represent “Copy No More” (line 4), then onceagain it does not matter whether the RAM is present. A copy is notallowed to be made. Display of the work is all that is allowed. (Displayis also allowed in all other lines.)

[0071] Finally, a “Copy Never” code (line 5) is treated just as is a“Copy No More” code since what they allow (or more accurately, what theydo not allow) is the same when they appear on a work.

[0072]FIG. 4B shows a truth table defining an alternate embodiment ofthe invention, with separate columns provided for bits 1 and 2 (markedP0 and P1, respectively) of the CGMS-A and the RC bit.

[0073] In summary, in the preferred embodiment of this invention, a workover which rights are asserted is marked in its analog form in threeways: (1) a primary CCI of CGMS-A in the vertical blanking interval, (2)a RAM encoded in VEIL modulation in the visible portion of the videoimage in one or more (preferably, more) places and with a plurality ofparameter settings to compensate for standards conversion that may takeplace, and (3) optionally, a SCCI using an audio watermark.

[0074] With this combination, circumvention requires a separate attackon each component of the marking system. Even without the optional SCCI,circumvention of the system requires that the CGMS-A information bemodified in order to change the rules governing use of the content,which is significantly more difficult than simply removing CGMS-A. Thus,the use of a RAM in combination with a CCI such as CGMS-A will besufficient to deter casual copying. The use of the RAM distinguishesbetween commercial and non-commercial works, and between works thateither never had CCI such as CGMS-A and works where the CCI has beenlost.

[0075] Although the invention has been described with reference to aparticular embodiment, it is to be understood that this embodiment ismerely illustrative of the application of the principles of theinvention. Numerous modifications may be made therein and otherarrangements may be devised without departing from the spirit and scopeof the invention.

What we claim is:
 1. A method for processing an analog video signal thatrepresents a work for which rights information is asserted, the signalincluding a rights assertion mark (RAM) in the video portion of thesignal within the visible picture such that capture of the picture willinclude the mark, and copy control information (CCI) bits in thevertical blanking interval of the signal for representing copying andredistribution rules; comprising the steps of: determining if the RAMand CCI bits are present in the work, if the RAM is present and the CCIbits are present, then applying the copying and redistribution rulesrepresented by the CCI bits, and if the RAM is present but the CCI bitsare not, then applying the most restrictive copying and redistributionrules that can be represented by the CCI bits.
 2. A method forprocessing an analog video signal that represents a work for whichrights information is asserted in accordance with claim 1 wherein theCCI bits are represented as CGMS-A information, the most restrictivecopying rule is “copy never”, and the most restrictive redistributionrule is “no redistribution.”
 3. A method for processing an analog videosignal that represents a work for which rights information is assertedin accordance with claim 2 wherein the RAM is represented by VEILmodulation of the video signal.
 4. A method for processing an analogvideo signal that represents a work for which rights information isasserted in accordance with claim 3 wherein the video signal furtherincludes secondary copy control information (SCCI) that conforms withthe CCI bits, and if the RAM and SCCI bits are present but the CCI bitsare not, then the copying and redistribution rules represented by theSCCI bits are applied.
 5. A method for processing an analog video signalthat represents a work for which rights information is asserted inaccordance with claim 4 wherein the SCCI bits are in the form of awatermark in the audio portion of the analog video signal.
 6. A methodfor processing an analog video signal that represents a work for whichrights information is asserted in accordance with claim 4 wherein theSCCI bits are in the form of a digital signature in the verticalblanking interval of the analog video signal, where the digitalsignature is a function of the CCI bits and selected pixels of thevisible picture of the work.
 7. A method for processing an analog videosignal that represents a work for which rights information is assertedin accordance with claim 1 wherein the RAM is represented by VEILmodulation of the video signal.
 8. A method for processing an analogvideo signal that represents a work for which rights information isasserted in accordance with claim 1 wherein the video signal furtherincludes secondary copy control information (SCCI) that conforms withthe CCI bits, and if the RAM and SCCI bits are present but the CCI bitsare not, then applying the copying and redistribution rules representedby the SCCI bits.
 9. A method for processing an analog video signal thatrepresents a work for which rights information is asserted in accordancewith claim 8 wherein the SCCI bits are in the form of a watermark in theaudio portion of the work.
 10. A method for processing an analog videosignal that represents a work for which rights information is assertedin accordance with claim 8 wherein the SCCI bits are in the form of adigital signature in the vertical blanking interval of the analog videosignal, where the digital signature is a function of the CCI bits andselected pixels of the visible picture of the work.
 11. A method forasserting and identifying rights information in a work represented by ananalog video signal, comprising the steps of: inserting a rightsassertion mark (RAM) in the video portion of the signal within thevisible picture such that capture of the picture will include the mark,and inserting copy control information (CCI) bits in the verticalblanking interval of the signal for representing copying andredistribution rules, where the signal is to be processed by a devicethat operates on it as follows: (i) if the RAM is present and the CCIbits are present, then the copying and redistribution rules representedby the CCI bits are applied, and (ii) if the RAM is present but the CCIbits are not, then the most restrictive copying and redistribution rulesthat can be represented by the CCI bits are applied.
 12. A method forasserting and identifying rights information in a work represented by ananalog video signal in accordance with claim 11 wherein the CCI bits arerepresented as CGMS-A information, the most restrictive copying rule is“copy never”, and the most restrictive redistribution rule is “noredistribution.”
 13. A method for asserting and identifying rightsinformation in a work represented by an analog video signal inaccordance with claim 11 wherein the RAM is represented by VEILmodulation of the video signal.
 14. A method for asserting andidentifying rights information in a work represented by an analog videosignal in accordance with claim 13 further including the step ofinserting in the signal secondary copy control information (SCCI) thatconforms with the CCI bits.
 15. A method for asserting and identifyingrights information in a work represented by an analog video signal inaccordance with claim 14 wherein the SCCI bits are in the form of awatermark in the audio portion of the work.
 16. A method for assertingand identifying rights information in a work represented by an analogvideo signal in accordance with claim 14 wherein the SCCI bits are inthe form of a digital signature in the vertical blanking interval of theanalog video signal, where the digital signature is a function of theCCI bits and selected pixels of the visible portion of the work.
 17. Amethod for processing an analog video signal that represents a work forwhich rights information is asserted, the signal including a rightsassertion mark (RAM) in the video portion of the signal within thevisible picture such that capture of the picture will include the mark,and copy control information (CCI) bits for representing copying rules;comprising the steps of: determining if the RAM and CCI bits are presentin the work, if the RAM is present and the CCI bits are present, thenapplying the copying rules represented by the CCI bits, and if the RAMis present but the CCI bits are not, then applying default copyingrules.
 18. A method for processing an analog video signal thatrepresents a work for which rights information is asserted in accordancewith claim 17 wherein the CCI bits are represented as CGMS-A informationin the vertical blanking interval of the analog video signal.
 19. Amethod for processing an analog video signal that represents a work forwhich rights information is asserted in accordance with claim 17 whereinthe RAM is represented by VEIL modulation of the video signal.
 20. Amethod for processing an analog video signal that represents a work forwhich rights information is asserted in accordance with claim 19 whereinthe video signal further includes secondary copy control information(SCCI) that conforms with the CCI bits, and if the RAM and SCCI bits arepresent but the CCI bits are not, then the copying and redistributionrules represented by the SCCI bits are applied.
 21. A method forprocessing an analog video signal that represents a work for whichrights information is asserted in accordance with claim 20 wherein theSCCI bits are in the form of a watermark in the audio portion of thework.
 22. A method for processing an analog video signal that representsa work for which rights information is asserted in accordance with claim20 wherein the SCCI bits are in the form of a digital signature in thevertical blanking interval of the analog video signal, where the digitalsignature is a function of the CCI bits and selected pixels of thevisible picture portion of the work.
 23. A method for asserting andidentifying rights information in a work represented by an analog videosignal, comprising the steps of: inserting a rights assertion mark (RAM)in the video portion of the signal within the visible picture such thatcapture of the picture will include the mark, and inserting copy controlinformation (CCI) bits in the signal for representing copying rules,where the signal is to be processed by a device that operates on it asfollows: (i) if the RAM is present and the CCI bits are present, thenthe-copying rules represented by the CCI bits are applied, and (ii) ifthe RAM is present but the CCI bits are not, then default copying rulesare applied.
 24. A method for asserting and identifying rightsinformation in a work represented by an analog video signal inaccordance with claim 23 wherein the CCI bits are represented as CGMS-Ainformation.
 25. A method for asserting and identifying rightsinformation in a work represented by an analog video signal inaccordance with claim 23 wherein the RAM is represented by VEILmodulation of the video signal.
 26. A method for asserting andidentifying rights information in a work represented by an analog videosignal in accordance with claim 23 further including the step ofinserting in the signal secondary copy control information (SCCI) thatconforms with the CCI bits.
 27. A method for asserting and identifyingrights information in a work represented by an analog video signal inaccordance with claim 26 wherein the SCCI bits are in the form of awatermark in the audio portion of the work.
 28. A method for assertingand identifying rights information in a work represented by an analogvideo signal in accordance with claim 26 wherein the SCCI bits are inthe form of a digital signature in the vertical blanking interval of theanalog video signal, where the digital signature is a function of theCCI bits and selected pixels of the visible picture portion of the work.